Electrochemical testing device

ABSTRACT

An electrochemical testing device for a specimen includes a receiving member, an auxiliary electrode, a work module, a clamping module, and a reference electrode. The receiving member receives an electrolytic solution and includes a surrounding wall having a bottom open end. The auxiliary electrode is mounted in the receiving member. The work module holds the specimen and includes at least one upper plate covering the open end to close the receiving member and having an opening connected fluidly to an interior of the receiving member, a lower plate, a work electrode plate interposed between and contacting the upper and lower plates, and a test specimen holding site provided at the work electrode plate and connected fluidly to the opening. The clamping module clamps the work module against the surrounding wall. The reference electrode is disposed in the receiving member above the work electrode plate.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of Taiwanese application No.094145244, filed on Dec. 20, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an electrochemical testing device, more particularly to an electrochemical testing device which can evaluate properties of a respective one of components of a fuel cell.

2. Description of the Related Art

Recently, fuel cells have been developed as alternative energy sources in view of energy crisis and environmental protection. In order to improve the performance of the fuel cells, it is necessary to conduct various tests for the fuel cell.

Current testing devices generally rely on a whole cell to perform analysis so that it is impossible to evaluate the performance of a single electrode, or the influence of a basic component, such as a gas diffusion layer, a catalyst layer or a proton conducting membrane, on an electrochemical reaction. Therefore, sufficient information about the properties of the fuel cell can not be obtained using current testing devices.

SUMMARY OF THE INVENTION

Therefore, the object of the present invention is to provide an electrochemical testing device which is useful for evaluating the properties of a single component of a fuel cell.

The electrochemical testing device for a specimen according to this invention includes a receiving member, an auxiliary electrode, a work module, a clamping module, and a reference electrode. The receiving member is adapted for receiving an electrolytic solution and includes a surrounding wall that has a bottom open end. The auxiliary electrode is mounted in the receiving member. The work module is adapted to hold the specimen and includes at least one upper plate covering the open end of the surrounding wall to close the receiving member and having an opening connected fluidly to an interior of the receiving member, a lower plate, a work electrode plate interposed between and contacting the upper and lower plates, and a test specimen holding site provided at the work electrode plate and connected fluidly to the opening. The clamping module clamps the work module against the surrounding wall. The reference electrode is disposed in the receiving member above the work electrode plate.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which:

FIG. 1 is an exploded perspective view of the preferred embodiment of an electrochemical testing device according to this invention;

FIG. 2 is a perspective view of the preferred embodiment;

FIG. 3 is a sectional view of the preferred embodiment in a first state of use; and

FIG. 4 is a sectional view of the preferred embodiment in a second state of use.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1, 2, and 3, the preferred embodiment of an electrochemical testing device for a specimen 6 according to this invention is shown to include a receiving member 1, an auxiliary electrode 2, a work module 3, a clamping module 4, a reference electrode 5, and a cover plate 36.

The receiving member 1 is adapted for receiving an electrolytic solution, and includes a surrounding wall 11 surrounding an axis (X) and having a bottom open end 121, a discharge hole 13 disposed in the surrounding wall 12, and a plug 14 removably closing the discharge hole 13.

The auxiliary electrode 2 is mounted in the receiving member 1, and includes an end portion 21 extending in a direction parallel to the axis (X). The auxiliary electrode 2 is a corrosion resistant conductor, and is made of a platinum-plated titanium web in this preferred embodiment.

The work module 3 is adapted to hold the specimen 6, and includes an upper plate 31, a work electrode plate 32, a lower plate 33, and a test specimen holding site 37.

The upper plate 31 covers the open end 121 of the surrounding wall 12 to close the receiving member 1 so as to receive the electrolytic solution in the receiving member 1 and has an opening 311 connected fluidly to an interior of the receiving member 1.

The work electrode plate 32 is interposed between and in contact with the upper and lower plates 31,33, and is a corrosion resistant conductor. In the preferred embodiment, the work electrode plate 32 is made of a highly dense graphite, which has electric-conducting, gas-sealing, and corrosion-resisting properties. The work electrode plate 32 has opposite first and second surfaces 322, 324, a fluid passage 321 between the first and second surfaces 322, 324, a fluid inlet 320 connected to the fluid passage 321, and a through slot 323 extending through the first surface 322 and connected fluidly to the fluid passage 321 and the opening 311.

The work module 32 further includes an osmotic block 34 spanning the opening 311 of the upper plate 31 and aligned with the through slot 323 of the work electrode plate 32, and a sealing ring 35 mounted between the upper plate 31 and the work electrode plate 32 and surrounding the test specimen holding site 37. The osmotic block 34 is made of a corrosion resistant and insulating porous material. In this preferred embodiment, the osmotic block 34 is made of porous glass.

The test specimen holding site 37 is provided at the work electrode plate 32 and is connected fluidly to the opening 311.

The cover plate 36 is disposed on top of the surrounding wall 12 and is clamped by the clamping module 4. The cover plate 36 has a through hole 361. The end portion 21 of the auxiliary electrode 2 extends outward through the through hole 361. The cover plate 36 further has a passage 362 for passing inert gas into the receiving member 1, and an aperture 363 for extension of the reference electrode 5 therethrough.

The clamping module 4 clamps the work module 3 against the surrounding wall 12, and is detachable from the work module 3 to change the position of the work electrode plate 32 so that the first and second surfaces 322,324 of the work electrode plate 32 can contact the upper plate 31 interchangeably. The clamping module 4 includes a plurality of bolts 41 penetrating through the work module 3, and a plurality of clamping screws 42 attached respectively to the bolts 41. The bolts 41 further penetrate the cover plate 36.

The reference electrode 5 is disposed in the receiving member 1 above the work electrode plate 32.

It should be noted that in the fuel cell analysis, a whole cell is a device including an anode reaction and a cathode reaction, whereas a half cell is a device which includes only a single electrode reaction, i.e., an anode or cathode reaction, and which can control the reaction. The electrochemical testing device of this invention is a half electrochemical cell, and the work electrode plate 32 of the electrochemical testing device of this invention can be used as an anode or a cathode of the whole cell.

Referring once again to FIGS. 2 and 3, the test specimen holding site 37 is a specimen receiving recess 325 formed in the first surface 322 of the work electrode plate 32 and aligned with the through slot 323 and the opening 311 when the first surface 322 contacts the upper plate 31. In this case, the electrochemical testing device of this invention can be used to evaluate the properties of a gas diffusion layer, a catalyst layer, or a proton conducting membrane with respect to electrochemical modification and exchange. The specimen 6 is made from a material such as the gas diffusion layer, the catalyst layer or the proton conducting membrane used in a fuel cell. The specimen 6 is disposed on the test specimen holding site 37 of the work module 3. The work module 3 is clamped against the surrounding wall 12 by the clamping module 4.

An electrochemical analysis instrument 7 is connected electrically to the reference electrode 5, the work electrode plate 32, and the auxiliary electrode 21. Gas used for the test is transported into the fluid passage 321 of the work electrode plate 32 via the fluid inlet 320. The gas used for the evaluation can be hydrogen or oxygen, which is selected according to whether the work electrode plate 32 is used as the anode or the cathode. For example, when the work electrode plate 32 is used as the anode, the gas transported into the fluid passage 321 is hydrogen. Hydrogen is oxidized into hydrogen protons and electrons. The hydrogen protons diffuse into the receiving member 1 through the osmotic block 34, and react with the electrolytic solution in the receiving member 1. The electrons travel to the auxiliary electrode 2 through the electrochemical analysis instrument 7. Since the reference electrode 5 provides a stable reference potential, the current and the potential of the work electrode plate 32 can be measured so as to evaluate the properties of the specimen 6.

Since the work electrode plate 32 is made of a highly dense graphite, which is thermo-resistant, the temperature of the work electrode plate 32 can be elevated to investigate the influence of temperature on the aforesaid reactions. Furthermore, the osmotic block 34 is made of porous glass, which can press the specimen 6 against the work electrode plate 32 so as to prevent the specimen 6 from deforming during the evaluation and to increase the accuracy of the evaluation. Additionally, the receiving member 1 is provided with a large receiving space to supply a sufficient amount of the electrolytic solution. The auxiliary electrode 2 surrounds the osmotic block 34 and therefore approaches the work electrode plate 32 as close as possible, thereby reducing the electric resistance between the auxiliary electrode 2 and the work electrode plate 32. The reference electrode 5, which abuts against the osmotic block 34, permits measurement of the current and potential at the most ideal position.

Referring to FIG. 4, the position of the work electrode plate 32 is changed so that the second surface 324 of the work electrode plate 32 contacts the upper plate 31. At this state, the test specimen holding site 37 is an area of the second surface 324 beneath the opening 311 of the upper plate 31. Therefore, the electrochemical testing device of this invention can be used for the evaluation of the characteristics of materials with respect to corrosion, plating, and electrochemical modification, polishing and etching, etc. The specimen 6 to be evaluated is positioned in the test specimen holding site 37. The area of the test specimen holding site 37 is limited by the sealing ring 35 so that the specimen 6 can have a constant current density. The electrolytic solution received in the receiving member 1 can pass through the opening 311 of the upper plate 31 and react with the specimen 6. The properties of the specimen 6 can therefore be evaluated.

In order to fit different sizes of the specimens 6, the work module 3 of the electrochemical device of this invention may be provided with a plurality of upper plates 31 having different sizes of the openings 311. Therefore, a proper one of the upper plates 31 can be selected according to the specific requirements.

In view of the aforesaid, the electrochemical testing device of this invention has the following advantages:

1) Since the electrochemical testing device of this invention is a half cell, the configuration thereof is relatively simple, the operation thereof is relatively easy, and the testing period thereof is reduced.

2) In addition to a half cell analysis, the electrochemical testing device of this invention can be used for tests relating to corrosion, plating, and electrochemical modification, polishing, etching, etc.

3) The work module 3 of the electrochemical device of this invention has a modular design which permits exchange of individual components (e.g., the upper plate 31) to conduct different tests.

While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements. 

1. An electrochemical testing device for a specimen, comprising: a receiving member adapted for receiving an electrolytic solution and including a surrounding wall that has a bottom open end; an auxiliary electrode mounted in said receiving member; a work module adapted to hold the specimen and including at least one upper plate covering said open end of said surrounding wall to close said receiving member and having an opening connected fluidly to an interior of said receiving member, a lower plate, a work electrode plate interposed between and contacting said upper and lower plates, and a test specimen holding site provided at said work electrode plate and connected fluidly to said opening; a clamping module for clamping said work module against said surrounding wall; and a reference electrode disposed in said receiving member above said work electrode plate.
 2. The electrochemical testing device as claimed in claim 1, wherein said work electrode plate has opposite first and second surfaces, said clamping module being detachable from said work module to change the position of said work electrode plate so that said first and second surfaces of said work electrode plate can contact said upper plate interchangeably.
 3. The electrochemical testing device as claimed in claim 2, wherein said work electrode plate further has a fluid passage between said first and second surfaces, a fluid inlet connected to said fluid passage, and a through slot extending through said first surface and connected fluidly to said fluid passage and said opening.
 4. The electrochemical testing device as claimed in claim 3, wherein said test specimen holding site is a specimen receiving recess formed in said first surface and aligned with said through slot and said opening when said first surface contacts said upper plate.
 5. The electrochemical testing device as claimed in claim 3, wherein said test specimen holding site is an area of said second surface beneath said opening when said second surface contacts said upper plate.
 6. The electrochemical testing device as claimed in claim 2, wherein said clamping module includes a plurality of bolts penetrating through said work module, and a plurality of clamping screws attached respectively to said bolts.
 7. The electrochemical testing device as claimed in claim 6, further comprising a cover plate disposed on top of said surrounding wall and clamped by said clamping module, said bolts further penetrating said cover plate.
 8. The electrochemical testing device as claimed in claim 7, wherein said cover plate has a through hole, said auxiliary electrode having an end portion extending outward through said through hole.
 9. The electrochemical testing device as claimed in claim 7, wherein said cover plate has a passage for passing inert gas into said receiving member.
 10. The electrochemical testing device as claimed in claim 7, wherein said cover plate has an aperture for extension of said reference electrode therethrough.
 11. The electrochemical testing device as claimed in claim 1, wherein said receiving member includes a discharge hole disposed in said surrounding wall, and a plug removably closing said discharge hole.
 12. The electrochemical testing device as claimed in claim 1, wherein said auxiliary electrode is made of a platinum-plated titanium web.
 13. The electrochemical testing device as claimed in claim 2, wherein said work module further includes an osmotic block spanning said opening of said upper plate and aligned with said through slot of said work electrode plate when said first surface contacts said upper plate.
 14. The electrochemical testing device as claimed in claim 13, wherein said osmotic block is made of porous glass.
 15. The electrochemical testing device as claimed in claim 1, wherein said work electrode plate is made of a highly dense graphite.
 16. The electrochemical testing device as claimed in claim 1, wherein said work module further includes a sealing ring mounted between said upper plate and said work electrode plate and surrounding said test specimen holding site.
 17. An electrochemical testing device for a specimen, comprising: a receiving member adapted for receiving an electrolytic solution and including a surrounding wall that has a bottom open end; an auxiliary electrode mounted in said receiving member; a work module adapted to hold the specimen and including at least one upper plate covering said open end of said surrounding wall to close said receiving member and having an opening connected fluidly to an interior of said receiving member, a lower plate, a work electrode plate interposed between and contacting said upper and lower plates, and a test specimen holding site provided at said work electrode plate and connected fluidly to said opening; and a reference electrode disposed in said receiving member above said work electrode plate, wherein said work electrode plate further has a fluid passage between said first and second surfaces, a fluid inlet connected to said fluid passage, and a through slot extending through said first surface and connected fluidly to said fluid passage and said opening. 